This invention relates to agricultural implements and in particular has to do with the means for controlling the operation of the beater and feed conveyor mechanisms of a manure spreader.
Most manure spreaders are tractor drawn. A generation ago most of the mechanisms for unloading the spreaders were powered from the rear wheels. In recent machines, power to drive the unloading mechanisms is taken from the power-take-off of the tractor.
In U.S. Pat. No. 2,342,837 to Brown a control device for a manure spreader is described wherein dual levers on the front end of the machine are used. The pair of levers are simultaneously movable between operative and inoperative first and second positions. Additionally, there is a third position which keeps the beater turning at the same speed as in the second position of the control levers but causes the conveyor to speed up. In the Brown system, both the beater and the conveyor receive motive power from the rear wheels of the spreader.
In U.S. Pat. No. 3,583,242 to Thornbloom a drive and control system for a manure spreader is described. The spreader includes two gear boxes, one of which drives the beater mechanism, the other drives the conveyor. Power is supplied to the gear boxes via a drive shaft extending along the right side of the spreader box. A sprocket and drive chain arrangement at the front of the spreader allows driving power to be received from the PTO shaft of the tractor used for towing the spreader. The input shaft of the beater gear box is in axial alignment with the drive shaft, there being a selectively engageable first clutch therebetween for connecting the beater gear box to the power source. The input shaft of the conveyor gear box is offset from, but in parallel axial alignment with the drive shaft. Between the conveyor input and the drive shaft there are two different speed chain and sprocket drives. A double sided second clutch couples in the conveyor gear box to the drive shaft via one or the other of the chain and sprocket drives. A neutral position on the clutch is also selectable. A control shaft extending down the side of the spreader box in parallel with the main drive shaft operates two cam plates which position and selectively engage the two clutch mechanisms. A pawl and ratchet mechanism is connected to the control shaft for indexing the cam plates to a total of six positions which represent compatible modes of operation for the conveyor and beater units.
In U.S. Pat. No. 3,722,307 to Campbell a drive system for a manure spreader is described wherein motive power to operate both the beater and conveyor units is supplied from the power-take-off of the tractor. The drive system includes a driving shaft mounted on the left side of the spreader. At the rear corner of the spreader, the shaft is operatively connected to two gear boxes, one of which drives the beater mechanism, the other the conveyor. A control lever mounted on the front of the spreader box, positionable in any of four notches is linked by cable to operatively select the driving arrangement between the shaft and the two gear boxes.
U.S. Pat. No. 4,196,859 to Trott et al describes a fourth type of spreader control. In Trott et al there is a manure spreader which includes conveyor and beater assemblies which are powered from the PTO of the towing tractor. A single hydraulic control operates both the conveyor and beater drives. There is a drive shaft along the left hand side of the spreader box which is coupled to the beater gear box. A second shaft positioned parallel with the first furnishes power to the conveyor gear box. At the front of the spreader box there is a jaw clutch which provides for engaging and disengaging a gear on the end of the power shaft which is in line with the PTO. A jaw clutch and variable speed pulley assembly are also mounted on the end of the power shaft. The variable speed pulley provides a belt drive to a second pulley on the end of the conveyor drive shaft. The jaw clutch and the variable speed pulley assembly are simultaneously controlled by a cam operated shifter assembly. The cam is mounted on a control shaft along with a pawl and ratchet mechanism which are indexed by the hydraulic cylinder. Use of the variable speed pulley assembly allows the operator to vary the operating speed of the conveyor.
This invention eliminates many of the disadvantages of the prior art machines. A single control is easily operated by a pull rope which extends from the front of the cargo box to the towing tractor. This allows the operator to manipulate the controls without leaving the tractor seat. Additionally, the invention improves on the prior art in that the drive train between the PTO shaft to the beater and conveyor gear boxes is simplified.